Many different types of synthetic intraocular lens structures have been developed to replace the natural lens of the human eye after lens removal during cataract surgery. During such operations, an opening or incision is made in the cornea and in the anterior surface of the capsular bag, commonly in the area adjacent to the pupilary aperture. The damage lens tissue is then removed by means of a vacuum tool resulting in a total loss of vision to the affected patient. In order to restore normal or correctable vision to the patient, a variety of lens structures have been developed which are designed to be affixed in the intraocular space of the eye. Such structures commonly comprise two portions: a centrally positioned lens and two or more appendages attached to the body of the lens which function to position and secure the lens in front of or just behind the pupil.
The artificial lens is formed from an optically clear substance and shaped so as to focus the impinging light onto the retina of the eye. Such lenses are commonly optically formed so as to be plano-convex, convex-plano or bi-convex. The appendages attached to the lens typically comprise flexible legs or resilient plastic or metal fibers which are designed to make point contact with the appropriate structures in the interior of the eye. One commonly employed type of intraocular lens structure is designed to position the lens in the anterior chamber of the eye just in front of the pupil. Such devices are designed to operate by wedging the flexible lens fibers or loops into the anterior chamber angle. Intraocular lens structures of this type are disclosed, for example, by K. J. Hoffer (U.S. Pat. No. 4,244,060), J. L. Tennant (U.S. Pat. No. 4,254,510), E. A. Rainin (U.S. Pat. No. 4,242,760), and C. D. Kelman (U.S. Pat. No. 4,343,050). Such structures may be inserted via loaded plastic sleeves which are then withdrawn from the eye leaving the lens structure to be positioned by conventional techniques as disclosed by A. Y. Anis in U.S. Pat. No. 4,251,887.
Although such intraocular lens structures have successfully addressed many of the problems associated with the restoration of vision following lens removal operations, their insertion and positioning within the eye presents many difficulties. In the first place, the use of discreet attachment appendages, such as flexible legs and loops, tends to localize contact of the structure with the supporting tissues. Such localized pressure can lead to distortion of the pupil and eye irritation. Furthermore, the support appendages which are attached to the lens body effectively increase the size of the lens and the dimensions of the incision which must be made in the eye in order to insert the structure. Especially in the case of elderly patients, such large incisions lead to increased recovery times and healing problems. Although resilient attachment means, such as those formed of plastic fibers, may be compressed prior to the insertion of the lens structure into the eye via the incision, their decompression, once the structure is within the eye may lead to a whipping action which can tear the iris and cause bleeding and other complications.
Furthermore, the need to minimize the size of the incision in the eye has heretofore resulted in the development of intraocular lens structures which comprise only one lens body. Such structures do not fully address the vision problems of patients who normally require bi- or trifocal-type lenses to correct near-far vision discrepencies.
Thus, a need exists for intraocular lens structures which can be inserted into the eye through minimally sized incisions and can be securely positioned within the eye without placing undue or localized pressure upon the structures of the eye. Furthermore, a need exists for intraocular lens structures which will introduce a plurality of lens bodies into the interior space of the eye while causing minimal trauma thereto.